The present invention relates to processors for photographic film, paper or the like and, more particularly, to such a processor having a system for automatically diluting processing chemicals and for mixing such chemicals.
As known from U.S. Pat. No. 3,418,913, issued Dec. 31, 1968 in the name of J. L. Snarr, processors for a photographic medium have a plurality of tanks for holding processing solutions, including a developer solution and a fixer solution followed by a tank for water used for washing the photographic medium. The processing solutions in the tanks are recirculated by withdrawing the solution through a filter located within the tank and then pumping the solution through a heat exchanger and back into the tank. Replenishment solutions are provided through a replenishment line or conduit under the control of solenoid operated valves. The replenishment solution is provided downstream from the outlet of the tank and before the solutions reach the pump so that the replenishment solution is mixed with solution from the tank and cooled prior to being delivered to the tank with previously used solution.
The solutions used for processing photographic mediums are commonly supplied by the manufacturer in a concentrated form, and they are diluted with water before being supplied to the tanks of the processor. Dilution of the solutions commonly is accomplished manually by an operator. The dilution process requires the time of the operator, which increases the cost of the processing operation. Also, manual mixing of the concentrated processing materials and water is subject to error, which can have an adverse affect on the quality of the processing operation. In addition, premixing or dilution of the processing solutions can reduce the life of the solutions because the solutions are subject to evaporation and deterioration as a result of evaporation. The diluted processing solutions typically are contained within the film processor, and may occupy a substantial amount of space within the processor.